Laminar

Definition

Laminar flow is a type of fluid flow in which the fluid travels smoothly in parallel layers, with minimal disruption between the layers. It contrasts with turbulent flow, where there is chaotic and irregular movement.

5 Must Know Facts For Your Next Test

1. In laminar flow, the velocity of the fluid is constant at any point within the fluid.
2. Laminar flow typically occurs at low Reynolds numbers (Re < 2000).
3. Poiseuille’s Law describes laminar flow through a cylindrical pipe, relating pressure difference, viscosity, length, and radius of the pipe.
4. The frictional force in laminar flow is proportional to the velocity of the fluid.
5. Applications of laminar flow include medical devices like syringes and IVs, as well as various engineering systems.

Review Questions

• What distinguishes laminar flow from turbulent flow?
• Under what conditions does laminar flow typically occur?
• How does Poiseuille’s Law relate to laminar flow in a pipe?

Related terms

Reynolds Number: A dimensionless number used to predict whether a fluid flow will be laminar or turbulent. It is calculated as $Re = \frac{\rho vL}{\mu}$ where $\rho$ is density, $v$ is velocity, $L$ is characteristic length, and $\mu$ is dynamic viscosity.

Poiseuille’s Law: A law that provides a relationship between the volumetric flow rate through a cylindrical pipe and factors such as pressure difference, viscosity of the fluid, length of the pipe, and radius of the pipe. Expressed as $Q = \frac{{\Delta P \pi r^4}}{{8 \eta L}}$.

Viscosity: A measure of a fluid's resistance to deformation or shear stress. It quantifies how thick or sticky a fluid is.